Hole sealing and drilling method for downhole gas extraction in coal mine

Abstract

The invention discloses a hole sealing and drilling method for downhole gas extraction in a coal mine, which comprises the following steps of: 1) plugging a hole sealing baffle bag I filled with a baffle foaming material, a hole sealing filling bag I filled with a filling foaming material and a hole sealing baffle bag II filled with the baffle foaming material into an extraction drilling hole in sequence; 2) after the baffle foaming material and the filling foaming material are formed and cured, connecting a gas extraction tube to an extraction system to examine whether the extraction drilling hole is of air leakage or not; and 3) if so, further plugging a hole sealing filling bag II filled with the filling foaming material and a hole sealing baffle bag III filled with the baffle foaming material into the extraction drilling hole in sequence till the extraction drilling hole is not of air leakage. The method provided by the invention solves the problem that air leakage occurs after the extraction drilling hole is sealed in the extraction process and the hole cannot be repeatedly sealed, and enables the extraction drilling hole to prevent air leakage. Hole sealing depth and length can be adjusted randomly according to actual demands, so that various downhole gas extraction drilling holes in coal mines can be sealed.

Description

technical field [0001] The invention relates to the technical field of gas drainage drilling and sealing, in particular to a method for drilling and sealing gas drainage underground in coal mines. Background technique [0002] Coal mine gas extraction is a high-quality energy resource. According to statistics, in 2010, the total amount of gas extracted from coal mining areas in my country was nearly 7.5 billion m 3 , but the total amount of directly used drainage gas is only 2.3 billion m 3 , the utilization rate is only about 31%, and a large amount of extracted gas is directly discharged, which not only wastes resources, but also pollutes the atmospheric environment (the main component of gas is methane, whose greenhouse effect is 21 times that of carbon dioxide). One of the important reasons leading to a large amount of gas resources being directly emptied is that the concentration of gas extracted from coal mines is low and the utilization cost is high. The main reaso...

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Problems solved by technology

[0002] Coal mine gas extraction is a high-quality energy resource. According to statistics, in 2010, the total amount of gas extracted from coal mining areas in my country was nearly 7.5 billion m 3 , but the total amount of directly used drainage gas is only 2.3 billion m 3 , the utilization rate is only about 31%, and a large amount of extracted gas is directly discharged, which not only causes waste of resources, but also causes pollution to the atmospheric environment (the main component of gas is methane, and its greenhouse effect is 21 times that of carbon dioxide)

One of the important reasons leading to a large amount of gas resources being directly emptied is that the concentration of gas extracted from coal mines is low and the utilization cost is high

The main reason for the low concentration of gas in the drainage of a large number of coal mines is that the sealing effect of the drainage drilling is poor, and there is gas leakage.

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